A pipeline, or long length of pipe, is made up of a plurality of joints of pipe, or pipe sections. Each pipe section has opposed ends joined to another pipe section. A pipeline often varies from less than one inch inside diameter to more than a foot outside diameter. Sometimes, the fluid conveyed by a pipeline is corrosive. Therefore, the interior of the individual pipe sections is often coated with a heat sensitive plastic material in order to protect the internal surface of the pipe sections and thereby elongates the life of a pipeline.
When the pipe ends of internally coated pipe sections are joined by butt welding, for example, the heat from the welding operation destroys a substantial amount of the internal heat sensitive coating at the joined area. This is especially so with an epoxy resin coating which melts at about 420.degree. F. It stands to reason that the welded joint, which is usually the strongest part of the pipeline, soon becomes the weakest part of the pipeline due to the deleterious effects of corrosion acting on the unprotected joined area of the pipe sections.
It would therefore be desirable to be able to join together pipe sections into a continuous length in such a manner that the internal coating of the pipe is not harmed. This heretofore unknown and desirable welding operation would provide a continuous length of undamaged, internally coated pipe which should last for many years, and which would be much safer to persons and things in close proximity to the pipeline because its structural integrity would remain at its designed strength for an extended length of time.
A few previous solutions to this perplexing problem has been suggested by the following U.S. patents:
U.S. Pat. No. 2,895,747, 07/21/59, Bland et al. PA0 U.S. Pat. No. 3,325,191, 06/13/67, Yates. PA0 U.S. Pat. No. 3,890,483, 06/17/75, Webster. PA0 U.S. Pat. No. 3,892,032, 07/01/75, Bagnulo. PA0 U.S. Pat. No. 3,965,555, 06/29/76, Webster et al. PA0 U.S. Pat. No. 4,355,664, 10/26/82, Cook et al. PA0 U.S. Pat. No. 4,357,745, 11/09/82, Chlebowski. PA0 U.S. Pat. No. 4,611,833, 09/16/86, Lescaut. PA0 U.S. Pat. No. 4,640,532, 02/03/87, Pope. PA0 U.S. Pat. No. 4,681,349, 07/21/87, Press et al.
However, it is evident that none of the cited references provide a pipe connector as defined by the claims of this invention.
The present invention is an improvement over all of the above listed, previous patents because of the preservation of the structural integrity of the effected weldment over a long period of time; the lower cost of the novel pipe sections; the cost of the pipeline building operation is reduced: the heat flow characteristics are uniquely controlled during the joining of adjacent pipe sections; and particularly, the protection of the internal coating of the joined area of the pipe sections during the joinder operation.